Testing clip and circuit board contacting method

ABSTRACT

A testing clip for electrical connections between a wire and points, surfaces or pins, which thus are connected to electric and electronic measuring and testing equipment and generators. The clip has a hand-held unit, a gripping unit and a resilient device providing connections both by direct hand-held pointing and by hitching on, offering good accessibility to narrow places and good insulation between the operator and the signal. The contacts are performed by a tip of the electrically conductive needle, which is a part of the hand-held unit and to which the wire is connected. The gripping rod, attaches the clip to the device to be tested by the hitch on procedure.

CROSS REFERENCE TO RELATED APPLICATION

This application is a national phase of PCT/RO91/00003 filed 19 Dec.1991 and based, in turn, on a Romanian national application 146,608filed 20 Dec. 1990 and a Romanian national application 148,260 filed 15Aug. 1991 under the International Convention.

FIELD OF THE INVENTION

The present invention relates to a testing clip for providing theelectrical connections of a connecting wire to points to be contactedand tested. More particularly this invention relates to a device formaking connections between points, conductive surfaces or pins andelectric and electronic measuring equipment and generators. Theinvention relates also to a circuit board contacting method, providingelectrical connections of testing clips to circuit boards.

BACKGROUND OF THE INVENTION

Known testing probes can include probes which have an electricallyconductive metallic needle, included in an insulated body of the probeand connected to a connecting wire. This probe has no grippingpossibilities to perform hitch on connections to test points and theoperator-signal insulation may not be sufficient, as it depends on thethickness of the body.

Probes can also have a hollow sleeve body receiving a mobile rod. Themobile rod is connected to the connecting wire, has a hooked end, iselectrically conductive and acts as the testing contact. This probe hashitching on capability, but is disadvantageous because the directpoint-contact is unwieldy and tiring, requiring continuous pressure onthe button. Also the insulation between the operator and the signal maynot be sufficient.

Alligator clips can be used which comprise two conductive jaws rotatingon a pivot and compressed by a spring. One of the jaws is connected tothe connecting wire. The alligator clip has gripping possibilities, butpoor direct pointing contact performance, especially in narrow places,and also very poor insulation between the operator and the electricalsignal.

Existing probes do not offer good testing performance in both contactmodes, i.e. direct point contact and hitching on. Moreover the probes donot offer very good operator-signal insulation and do not enable hitchon, hands free connections on the circuit boards.

OBJECTS OF THE INVENTION

The object of this invention is to provide a testing clip which achievesgood performance, and has low contact resistance in the two testingmodes, namely direct pointing and hitching on. The clip should providereliable contact on points, surfaces, pins, wires, and electronicdevices even in narrow places. The clip also should provide very goodoperator-signal insulation. In the hitch-on connection, the clip shouldhave only low stress on the contacting parts. The clip should alsoprovide hitch-on opportunities on electronic circuit boards on the edgesof the holes performed in the board. Connections to one or severalpoints of the circuit should also be available by the circuit boardcontacting method.

SUMMARY OF THE INVENTION

According to the invention, a testing clip is provided, comprising ahand-held unit or handle, a gripping unit, a resilient device and aconnecting wire.

The hand-held unit comprises a hollow outer sleeve made of insulatingmaterial on one side of which a needle is fixed, preferably by means ofa support. The needle is made of an electrically conductive material,such as metal. The outside end of the needle is used to make theelectrical contacts to test points, and the inside end is electricallyconnected to the conductive wire.

The needle can have different shapes. In a preferred embodiment of thisinvention it is a metal sheath.

In an alternative arrangement the needle is not hollow and has a forkedtip while the hooked rod can slide along the needle performing thegripping when necessary. The testing needles are fixed in the support,preferably made of a rigid insulating material, such as plastic. Thejoint between the support and the sleeve is preferably detached, forinstance, by threading.

Preferably, a finger grip is provided on the sleeve to allow theoperator to hold the clip with the fingers of only one hand, whileforcing the button inwardly with the thumb or the palm of the same hand.This allows easy one-hand operation.

The gripping unit comprises a rod, preferably hooked, and a button. Thehooked end of the rod is guided by a guide. The guide is hollow, insideor outside the needle, preferably parallel to the axis of the needle. Atthe unhooked end of the rod is the button made of insulating material.By pushing the button, the gripping unit assumes the protruding positionwith the hook of the rod protruding from the hand-held unit. Byreleasing the button, the resilient device, preferably a metal spring,urges the gripping unit into the retracted position, with the rodretracted into the hand-held unit.

The rod can be made of a conductive material, for example metal,providing good mechanical grip and better electrical contact, or can bemade of insulating material for improved accessibility and betterprevention of short-circuits.

The wire connected to the needle, emerges, by a canal or passage insidethe support or the sleeve. The canal is, preferably, at a short distancefrom the tip of the needle. This path of the wire creates only a lowstress when the clip is hanging on a testing point due to the shortdistance to the force produced by weight of the wire or by movement ofthe wire. This path of the wire keeps the electrical signal far from theoperator, providing high signal-operator insulation and offersprotection to the operator from high voltage signals and low influenceon the signal by the operator.

To provide direct point contact, the needle of the clip is placed on thepoint to be tested, the hook of the rod being retracted. The grippingunit in this retracted position, is pressed by the spring to a limitingshoulder on the hollow outer sleeve.

When the clip is to be hitched on, the button is pressed with a finger,bringing the hook to the protruding position. The hook is hung on thedevice to be tested, and when the finger is released, the hooked roddraws in, thus gripping the tested device between the hook and theneedle. The needle is brought in contact with the desired test point.The gripping unit slides inside the hand-held unit, the hooked rodslides along a guide inside the needle or the support, and the buttonslides inside the hollow of the sleeve.

An important facility offered by this invention is the possibility ofhitching the clip on the edges of circuit boards. To perform connectionsby the circuit board contacting method, the board is provided withholes. Preferably, the holes have a size and shape to allow the hookedrod to enter. At the withdrawing of the rod, the clip can be hitched onthe circuit board.

The test points are the common metallic parts of the circuit arrangednear edges. The testing needle is pointed to the desired point on thecircuit while the rod clasps the edge of the board.

In another embodiment of the invention, intended to permit multipleconnections on circuit boards, two or more needles are fixed onto thesupport. On one side of the needles the contact is made to the testpoints and on the other side the wires are connected to the electricalmeasuring equipment.

Another embodiment of the invention has the ability to provide, by thesame procedure, many connections to circuit boards and has a goodgripping on the circuit board using two gripping units.

In another embodiment of the invention, where the wire is a coaxialshielded wire, the support has a metal shield on the outer side,connected to the shield of the coaxial wire, to provide best protectionfor the signal.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIG. 1 is a perspective view of a preferred embodiment of the presentinvention with the gripping unit in the retracted position;

FIG. 2 is a view of part of the testing clip gripping and contacting awire;

FIG. 3 is a view of part of the testing clip gripping and contacting awire;

FIG. 4 is a cross-sectional view taken along the line IV--IV of FIG. 1;

FIG. 5 is a cross-sectional view of another embodiment of the inventionwith the guide for the rod inside the support, the testing clip grippinga wire between the needle and the hooked rod;

FIG. 6 is a cross-sectional view of the testing clip of FIG. 5 with thegripping ensemble in the retracted position;

FIG. 7 is a view of another embodiment of the invention in the form of ashielded testing clip connected to a shielded wire;

FIG. 8 is a longitudinal cross-sectional view of the testing clip fromFIG. 7;

FIG. 9 is a view of a circuit board provided with a hole and test pointsfor testing, according to the circuit board contacting method;

FIG. 10 is a view of a part of the testing clip hitched on for testingon the circuit board of FIG. 9;

FIG. 11 is a longitudinal cross-sectional view of the devices of FIG.10;

FIG. 12 is a partial cross-sectional view of another embodiment of theinvention in the form of a testing clip with several testing needlesconnected to test points on a circuit board;

FIG. 13 is a cross-sectional view of the device of FIG. 11; and

FIG. 14 is a cross-sectional view of another embodiment of the inventionin the form of a testing clip with several testing needles and twogripping units, connected on a circuit board.

SPECIFIC DESCRIPTION

The detailed description set forth below in connection with the appendedFigures is intended, merely, as a description of the presently preferredembodiments of the invention, and is not intended to represent the onlyform in which the present invention may be constructed or utilized.

FIGS. 1 and 2 show a testing clip 80 according to a preferred embodimentof the invention. The clip 80 basically comprises a hand-held unit 2, agripping unit 3, a resilient device 4 and an insulated wire 70.

The hand-held ensemble 2 comprises a hollow outer sleeve 20, a tubularsupport 30, and a testing needle 40. The sleeve 20 is made ofelectrically nonconductive material, such as plastic, and has on one enda sleeve-joint 23, in the preferred embodiment with a thread 24, bywhich the sleeve-support joint is made.

For limiting the movement of the gripping unit 3, at the other end ofthe sleeve 20, there is a limiting shoulder 21.

The support 30 is made of electrically nonconductive material, such asplastic, and has on one side the complementary part of the joint, thesupport-joint 31 in this embodiment with a thread 32. On the support 30is fixed a testing needle 40, made of conductive material, such asmetal. The needle 40 in this embodiment of the invention is a sheathwith the hollow acting as a guide 34 for the rod 50. At the outer sideof the needle 40 is the tip 41, preferably sharp, to insure good contacton the test points. On the other side of the needle 40, there is anelectrical and mechanical connection to the wire 70. In the preferredembodiment of the invention, the wire has an insulation 71 and theconnection 43 is made by soldering.

The gripping unit 3 of the testing clip comprises the rod 50 and thebutton 60, which are mechanically fixed together. The rod 50 has a hook51 on one end and the other end 52 is attached to the button 60. The rod50 can slide through the guide 34 inside the needle. In the preferredembodiment of the invention, as presented in FIG. 4, the rod crosssection is rectangular and the hollow in the needle is about the sameshape.

The rod is made of a tough enough material to resist pressure whengripping is performed and this material can be metal in order to obtainbetter electrical contacts, or it can be an insulating material, to getbetter accessibility and a better prevention against short-circuits.

The button 60 is made of an insulated material, such as plastic, has aninner part which is guided inside the sleeve and an outer end 62 to bepressed with the finger when gripping of the clip is to be prepared. Thebutton has a limiter, in the preferred embodiment of the invention ashoulder 61, which acts in conjunction with a complementary sleevelimiter 21 in establishing the movements of the gripping unit 3.

The resilient device 4 biases the gripping ensemble inside the sleeve.The resilient device, in the preferred embodiment of the invention, is ametal spring.

Operation of the clip, to test and connect, will now be described indetail.

For using the test clip by direct point contact, the clip has to be heldby keeping the sleeve in the hand and the tip 41 of the needle 40 ispressed against the desired point to be tested while the grippingensemble is in the retracted position. For better handling, the sleeve20 is provided with a finger grip 22 in the form of an annular flange,allowing single handed operation.

For the hands-free, hitch-on feature, the testing clip has to be fixedto the testing point. By pressing with the finger on the end 61, thebutton 60 is forced toward the sleeve 20, moving the gripping unit tothe advanced position (FIG. 2). The hooked end of the rod is protrudingfrom the guider 34 of the needle 40. The hook 51 is hooked onto thedevice to be tested and when the button 60 is released, the resilientdevice 4 presses between the button 60 and the support 30, gripping thetested device between the hook 51 and the needle 40, as seen in FIG. 3.

In an alternative embodiment of the invention, shown in FIG. 5 and FIG.6, the hollow guide 34 is inside the support 30, near and along theneedle 40. The grip for the hands-free testing of the embodiment of FIG.5 occurs at the release of the gripping ensemble from the advancedposition. In FIG. 6 the rod 50 is in the retracted position and theneedle 40 is free to perform the contact to the tested device 10.

In another embodiment of the invention, not presented in the drawing,two connecting wires, instead of one, are connected to the inside end ofthe needle, offering very low electrical resistance for specifictwo-wire electronic measurements.

In another embodiment of the invention, shown in FIG. 7 and FIG. 8, thetesting clip 82 is connected to a shielded wire 70 and the clip itselfhas a shielded testing needle, for improved performance on specificapplications such as with high frequencies. The support 30 has an outermetal shield 35, and the coaxial wire 70 has the outer metal shield 73electrically and mechanically connected to the shield 35, in thisembodiment by soldering. The central cable 71 of the wire 70 iselectrically and mechanically connected to the testing needle 40, inthis embodiment of the invention by soldering.

In another embodiment of the invention, not presented in the drawing,the gripping ensemble comprises two rods fixed on the same button at oneend, preferably with hooks opposing each other at the other end. Therods are guided inside the same guide and a better gripping by the clipcan result.

The testing clip has the possibility to make hitch-on, hands-freeconnections on the circuit boards, as shown in FIGS. 10 and 11. Thecircuit board 11 is provided with holes 13 and a metallic circuit path15. The holes 13 have a shape and size to allow the passing of the rod50 and the fastening of the clip on the board. Preferably, the hook 51is then gripped on the edge 14 and the tip 51 of the needle 50 ispointed on the test point 12.

FIGS. 12 and 13 show another embodiment of the invention which canprovide more than one contact on the circuit boards 11, speciallyprovided for this method, as presented before, with holes 13 and atypical path of the circuit 15. The testing clip has several testingneedles 40 fixed in the support 30. The needles have preferably a sharptip 41 to provide reliable contacts and they are connected to the wires70 by the connection 43. The clip is to be fastened onto the circuitboard 11, by the rod 50, preferably by the hook 51 on the edges 14 ofthe hole 13 made in the circuit board. The clip assumes the positionthat brings the testing needles 40 to the contacting points 12 of themetallic circuit of the circuit board 11.

Another embodiment of the invention, presented in FIG. 14, has theability to provide, by the same procedure, many connections to circuitboards and achieves good gripping on the circuit board using twogripping units.

I claim:
 1. A test probe, comprising:a handle formed by an electrically insulating elongated sleeve; an electrically insulating tubular guide formed at one end of said sleeve; a metallic test needle anchored in said guide and extending at most limitedly beyond said guide into said sleeve, said needle having a contact end projecting longitudinally from said guide and formed with a contact point for direct engagement with an electrical test connection by pressing of said needle thereagainst; an insulated wire connected to said needle remote from said contact point, within said sleeve but proximal to said one end of said sleeve for electrical connection of the probe to test equipment; a rod extending through said guide and longitudinally guided therein, said rod having a hook retractable toward said guide inwardly past said point into a retracted position and extendable outwardly past said point into an extended position upon displacement of said rod in said sleeve; a button affixed to said rod in said sleeve, projecting axially from said sleeve at an opposite end thereof, and manually displaceable to retract and extend said hook, whereby said hook can engage a structure and hold said point against an electrical test connection; and resilient means in said sleeve biasing said button away from said guide and drawing said hook toward said retracted position.
 2. The probe defined in claim 1 wherein said needle is tubular and said rod is guided in said needle.
 3. The probe defined in claim 2 wherein said rod and said needle have generally rectangular cross sections.
 4. The probe defined in claim 1 wherein said resilient means is a coil spring braced between said guide and said button.
 5. The probe defined in claim 1 wherein said wire extends outwardly from said probe around said one end of said sleeve.
 6. The probe defined in claim 1 wherein said wire is a coaxial conductor having a core connected to said needle and a shield connected to a shield extending around said guide. 